Faking Templates

Isolator++ Professional supports faking template classes. The syntax is the same as faking concrete classes.

Let's say we want to change the behavior of a template method:

template <class K>

class MyTemplateClass {

   K a, b;

public:

   MyTemplateClass(K _a, K _b) { a = _a; b = _b; }

   K getSum() { return a + b; }

};

We'll use the FAKE and WHEN_CALLED macros:

TEST_F(TemplatesTests, MyTemplateClass_getSum_Return7) 

{

   // Arrange

   auto fake = FAKE<MyTemplateClass<int>>();

   WHEN_CALLED(fake->getSum()).Return(7);

   // Act

   int num = fake->getSum();

   // Assert

   ASSERT_EQ(num, 7);

}

Faking multiple type templates works the same way:

template <class T1, class T2>

class MyTemplateClass {

   T1 t1;

   T2 t2;

public:

   MyTemplateClass(T1 _t1, T2 _t2) { t1 = _t1; t2 = _t2; }

   T1 getSum() { return t1 + static_cast<T1>t2; }

};

TEST_F(TemplatesTests, MyTemplateClass_getSum_Return7) 

{

   // Arrange

   auto fake = FAKE<MyTemplateClass<long,int>>();

   WHEN_CALLED(fake->getSum()).Return(7);

   // Act

   int num = fake->getSum();

   // Assert

   ASSERT_EQ(num, 7);

}

NOTE: To fake multiple type templates on Linux you'll need to use a typedef.

typedef MyTemplateClass<long,int> MyTemplate_long_int; // Necessary only on Linux

auto fake = FAKE<MyTemplate_long_int>();